/Engine/Source/Runtime/Engine/Classes/Kismet/KismetInternationalizationLibrary.h
Given a list of available cultures, try and find the most suitable culture from the list based on culture prioritization. eg) If your list was [en, fr, de] and the given culture was "en-US", this function would return "en". eg) If your list was [zh, ar, pl] and the given culture was "en-US", this function would return the fallback culture.
The culture as an IETF language tag (eg, "zh-Hans-CN").
static [FString](API\Runtime\Core\Containers\FString) GetSuitableCulture ( const [TArray](API\Runtime\Core\Containers\TArray)< [FString](API\Runtime\Core\Containers\FString) > & AvailableCultures, const [FString](API\Runtime\Core\Containers\FString) & CultureToMatch, const [FString](API\Runtime\Core\Containers\FString) & FallbackCulture )